C. Anyone
Because anyone is a demonstrative pronoun
The abreviation after a word in a dictionary tell you what part of speech the word is. Such as noun (n), pronoun (pron), adjective (adj), adverb (adv), verb (vb), conjunction (conj), preposition (prep), or interjection (interj).
In an essay it should only be one I'm pretty sure, but in a narrative as many as it takes to explain a lesson learned. If you were writing a book your conclusion would be whatever comes to you and whatever you feel the characters would do/say/feel.
Answer:
the third one. many people think that it is impossible to introduce a dog into a household that already has a cat.